NCCER 26410 EXAM QUESTIONS WITH CORRECT ANSWERS

NCCER 26410 EXAM QUESTIONS
WITH CORRECT ANSWERS



The recommended minimum polarization index for an AC motoris________.
1
2
3
4 - Correct Answers -2

NEMA's usual service conditions include a frequency variation of NOT more than .
5% of the nameplate frequency
10% of the nameplate frequency
15% of the nameplate frequency
20% of the nameplate frequency - Correct Answers -5% of the nameplate frequency

When a motor is powered down, unusual bearing noise may be detected by using a(n) .
megger
infrared thermometer
stethoscope
vibration tester - Correct Answers -stethoscope

The loss of a single phase of a polyphase motor can cause_________.
bearing damage
failure of the remaining phase windings
insulation damage
excessive noise and vibration - Correct Answers -failure of the remaining phase
windings

The first time a motor is started, it should be allowed to run.
with load for 10 minutes
with load for 1 hour
without load for 10 minutes
without load for 1 hour - Correct Answers -without load for 1 hour

Endplay adjustment is generally done on large motors with __________.
fixed bearings
adjustable bearings
a soft foot
ins - Correct Answers -adjustable bearings